Spring Data JPA - 多个 EnableJpaRepositories

Question

我的应用程序有多个数据源，所以我基于这个 URL 创建了两个数据源配置类.

但是在运行 spring boot 应用程序时出现错误

Description:Field userDataRepo in com.cavion.services.UserDataService required a bean named 'entityManagerFactory' that could not be found.Action:Consider defining a bean named 'entityManagerFactory' in your configuration.

从此Question在 StackOverflow 上帮助我找出了问题。我需要在我的 JPA 存储库中指定 entityManagerFactoryRef。

但是我有很多存储库类，其中一些使用 Entitymanager 'A' ，其中一些使用 'B' 。我目前的spring boot应用类是这样的

@SpringBootApplication(exclude = { DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class,
    DataSourceTransactionManagerAutoConfiguration.class })
@EnableTransactionManagement
@EntityScan("com.info.entity")
@ComponentScan({"com.info.services","com.info.restcontroller"})
@EnableJpaRepositories("com.info.repositories")
public class CavionApplication {

public static void main(String[] args) {
    SpringApplication.run(CavionApplication.class, args);
}
@Bean
public CommandLineRunner commandLineRunner(ApplicationContext ctx) {
    return args -> {

        System.out.println("Let's inspect the beans provided by Spring Boot:");

        String[] beanNames = ctx.getBeanDefinitionNames();
        Arrays.sort(beanNames);
        for (String beanName : beanNames) {
            System.out.println(beanName);
        }

    };
}}

我已经在 spring boot 类上给出了 EnableJpaRepositories ，那么如何配置多个 EnableJpaRepositories 以便我可以配置多个 entityManagerFactory ？

请建议设置多个数据源的最佳方法。

Answer 1

为了让 spring 知道什么 DataSource 与什么 Repository 相关，你应该在 @EnableJpaRepositories 注释中定义它。假设我们有两个实体，Servers 实体和 Domains 实体，每个实体都有自己的 Repo，然后每个 Repository 都有自己的 JpaDataSource 配置。

1.根据与它们相关的数据源对所有存储库进行分组。例如

Domains 实体的存储库(包:org.springdemo.multiple.datasources.repository.domains):

package org.springdemo.multiple.datasources.repository.domains;

import org.springdemo.multiple.datasources.domain.domains.Domains;
import org.springframework.data.jpa.repository.JpaRepository;

public interface DomainsRepository extends JpaRepository<Domains,Long> {
}

Servers 实体的存储库(包:org.springdemo.multiple.datasources.repository.servers)

package org.springdemo.multiple.datasources.repository.servers;

import org.springdemo.multiple.datasources.domain.servers.Servers;
import org.springframework.data.jpa.repository.JpaRepository;

public interface ServersRepository extends JpaRepository<Servers,Long> {
}

<强>2。您需要为每个 JPA 数据源定义一个配置，在此示例中，我将展示如何配置两个不同的数据源

Domains Jpa 配置:数据源和存储库之间的关系在 basePackages 值中定义，这就是为什么需要将存储库分组到不同的包取决于每个 repo 将使用的实体管理器。

@Configuration
@EnableJpaRepositories(
        entityManagerFactoryRef = "domainsEntityManager",
        transactionManagerRef = "domainsTransactionManager",
        basePackages = {"org.springdemo.multiple.datasources.repository.domains"}
        )
public class DomainsConfig {

Servers 数据源配置:如您所见，basePackages 值具有 Servers Repository 的包名称，以及 entityManagerFactoryRef 的值> 和 transactionManagerRef 不同是为了让 spring 将每个 entityManager 分开。

@Configuration
@EnableJpaRepositories(
        entityManagerFactoryRef = "serversEntityManager",
        transactionManagerRef = "serversTransactionManager",
        basePackages = {"org.springdemo.multiple.datasources.repository.servers"}
        )
public class ServersConfig {

3.将一个数据源设置为主

为了避免错误信息:org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration 中构造函数的参数 0 需要单个 bean，但找到了 2 个: 只需设置其中之一数据源为@Primary，在此示例中，我选择 Servers 数据源作为主要数据源:

@Bean("serversDataSourceProperties")
@Primary
@ConfigurationProperties("app.datasource.servers")
public DataSourceProperties serversDataSourceProperties(){
    return new DataSourceProperties();
}



@Bean("serversDataSource")
@Primary
@ConfigurationProperties("app.datasource.servers")
public DataSource serversDataSource(@Qualifier("serversDataSourceProperties") DataSourceProperties serversDataSourceProperties) {
    return serversDataSourceProperties().initializeDataSourceBuilder().build();
}

如果您需要更多信息，请查看每个配置的完整示例:

服务器 JPA 配置

@Configuration
@EnableJpaRepositories(
        entityManagerFactoryRef = "serversEntityManager",
        transactionManagerRef = "serversTransactionManager",
        basePackages = {"org.springdemo.multiple.datasources.repository.servers"}
        )
public class ServersConfig {

    @Bean(name = "serversEntityManager")
    public LocalContainerEntityManagerFactoryBean getServersEntityManager(EntityManagerFactoryBuilder builder,
                                                                          @Qualifier("serversDataSource") DataSource serversDataSource){


        return builder
                .dataSource(serversDataSource)
                .packages("org.springdemo.multiple.datasources.domain.servers")
                .persistenceUnit("servers")
                .properties(additionalJpaProperties())
                .build();

    }

    Map<String,?> additionalJpaProperties(){
        Map<String,String> map = new HashMap<>();

        map.put("hibernate.hbm2ddl.auto", "create");
        map.put("hibernate.dialect", "org.hibernate.dialect.MySQLDialect");
        map.put("hibernate.show_sql", "true");

        return map;
    }


    @Bean("serversDataSourceProperties")
    @Primary
    @ConfigurationProperties("app.datasource.servers")
    public DataSourceProperties serversDataSourceProperties(){
        return new DataSourceProperties();
    }



    @Bean("serversDataSource")
    @Primary
    @ConfigurationProperties("app.datasource.servers")
    public DataSource serversDataSource(@Qualifier("serversDataSourceProperties") DataSourceProperties serversDataSourceProperties) {
        return serversDataSourceProperties().initializeDataSourceBuilder().build();
    }

    @Bean(name = "serversTransactionManager")
    public JpaTransactionManager transactionManager(@Qualifier("serversEntityManager") EntityManagerFactory serversEntityManager){
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(serversEntityManager);

        return transactionManager;
    }
}

域 JPA 配置

@Configuration
@EnableJpaRepositories(
        entityManagerFactoryRef = "domainsEntityManager",
        transactionManagerRef = "domainsTransactionManager",
        basePackages = {"org.springdemo.multiple.datasources.repository.domains"}
        )
public class DomainsConfig {

    @Bean(name = "domainsEntityManager")
    public LocalContainerEntityManagerFactoryBean getdomainsEntityManager(EntityManagerFactoryBuilder builder
    ,@Qualifier("domainsDataSource") DataSource domainsDataSource){

        return builder
                .dataSource(domainsDataSource)
                .packages("org.springdemo.multiple.datasources.domain.domains")
                .persistenceUnit("domains")
                .properties(additionalJpaProperties())
                .build();

    }


    Map<String,?> additionalJpaProperties(){
        Map<String,String> map = new HashMap<>();

        map.put("hibernate.hbm2ddl.auto", "create");
        map.put("hibernate.dialect", "org.hibernate.dialect.H2Dialect");
        map.put("hibernate.show_sql", "true");

        return map;
    }


    @Bean("domainsDataSourceProperties")
    @ConfigurationProperties("app.datasource.domains")
    public DataSourceProperties domainsDataSourceProperties(){
        return new DataSourceProperties();
    }


    @Bean("domainsDataSource")
    public DataSource domainsDataSource(@Qualifier("domainsDataSourceProperties") DataSourceProperties domainsDataSourceProperties) {
        return domainsDataSourceProperties.initializeDataSourceBuilder().build();
    }

    @Bean(name = "domainsTransactionManager")
    public JpaTransactionManager transactionManager(@Qualifier("domainsEntityManager") EntityManagerFactory domainsEntityManager){
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(domainsEntityManager);

        return transactionManager;
    }

}

为了分离每个数据源，我将配置放在 application.properties 文件中，如下所示:

app.datasource.domains.url=jdbc:h2:mem:~/test
app.datasource.domains.driver-class-name=org.h2.Driver


app.datasource.servers.driver-class-name=com.mysql.jdbc.Driver
app.datasource.servers.url=jdbc:mysql://localhost:3306/v?autoReconnect=true&useSSL=false
app.datasource.servers.username=myuser
app.datasource.servers.password=mypass

如果您需要更多信息，请参阅以下文档:

Spring Documentation: howto-two-datasources

如何配置两个不同数据库的类似示例:github example